Vacuum ultraviolet excitation and emission properties ofPr3+andCe3+

Low-temperature investigation of electronic excitations in wide-gap materials doped with RE3+ or Cr3+ ions

“…Возможность такого процесса была детально теоретически проанализирована для многих материалов и экспериментально подтверждена для BaSO 4 :Pr 3+ [14]. В CaSO 4 :Tb 3+ был зарегистрирован слегка превышающий единицу квантовый выход η тербиевого свечения при передаче энергии возбужденного фотоном 8.44 эВ оксианиона сразу двум ионам Tb 3+ [15].…”

Recombination luminescence of CaSO4:Tb3+ and CaSO4:Gd3+phosphors

“…The Gd 3+ emission remaining at 430 K is tentatively connected with tunnel recombination of e and h localized near Gd 3+ (see next Section). Figure 1b shows the excitation spectra for strictly separated green and blue emissions of Tb 3+ centers in a CaSO 4 The excitation spectra for blue and green emissions in CaSO 4 :Tb 3+ ,F -undergo drastic changes with the rise of temperature from 10 K to 300 K (see Fig. 2b).…”

“…The aim of the present study is to analyze thoroughly the excitation recombination mechanisms of impurity lu-1 minescence in CaSO 4 :Tb 3+ and CaSO 4 :Gd 3+ phosphors, where the effective charge of RE 3+ ions substituting for Ca 2+ cations is compensated by either Na + ions [similar to 1,8] or F -ions. It has been shown earlier [see, e.g., 9,10] that at least three different types of recombination impurity luminescence occur in face-centered cubic alkali halide crystals doped with mercury-like s 2 ions (In + , Sn 2+ , Tl + , Pb 2+ ): (i) electron recombination luminescence, when conduction electrons ( ) recombine with the holes ( ) localized at/near impurity centers, (ii) hole recombination luminescence caused by the recombination of mobile holes with the electrons localized at/near impurity ions, and (iii) tunnel luminescence connected with the recombination between localized but spatially close and .…”

“…The possibility to use CaSO 4 :Tb 3+ [1][2][3] and BaSO 4 :Pr 3+ [4] phosphors as efficient spectral transformers in flu- * presented at the 7th International Conference on Functional Materials and Nanotechnologies, April 5-8, 2011, Riga, Latvia. † E-mail: aleksandr.lushchik@ut.ee orescent tubes is considered also.…”

“…The functioning of these transformers is based on the phenomena of photon multiplication [5,6] or photon cutting [7]. In CaSO 4 where the concentration of RE 3+ can be up to 5-7%, there is a total absorption of the exciting VUV-radiation, which provides either the direct excitation of the 4f n → 4f n-1 5d 1 intracentre transitions or the excitation of oxyanions (SO [2][3][4] ) and the formation of separated electrons and holes, with the subsequent energy transfer from the matrix to luminescence impurity centers [see, e.g., 8]. …”